The purpose of this study is to further delineate the genetic heterogeneity which has been shown to exist in osteogenesis imperfecta (O.I.), since a satisfactory classification has never been proposed. The proposal concentrates on detailed evaluation of portions of the phenotype never previously studied in detail: the dentition, hearing, and cardiovascular status. Probands ascertained from the files of the Moore Genetics Clinic as well as from local organizations of families with O.I. will be contacted and asked to participate. Histories, to include pedigree analysis, routine physical examination, otolaryngologic evaluation, dental examination (to include radiographs), echocardiogram and a full audiologic evaluation will be performed. Normally exfoliated and extracted teeth on patients with O.I. will be studied using the light and scanning electron microscopes to determine what differences exist between the teeth in the various forms of O.I. Genetic analysis will include the techniques of principal-components and cluster analysis to systematically identify subgroups. The study will provide accurate description of the phenotype of the various forms of O.I. prior to initiation of biochemical studies.